动态编译java类web项目答案

【问题标题】：Compile dynamically java class web project动态编译java类web项目
【发布时间】：2016-09-30 17:01:24
【问题描述】：

我正在开发一个 Web 应用程序，我可以在其中导入 Java 代码，编译然后执行它。这个类可能有一些来自其他库的导入，我将它们添加到我的类路径中。将它作为桌面应用程序运行，它可以工作，但是在 wildfly 9.0.2 下运行它没有找到我的类路径库，所以我在编译我的代码时出错。

我是否必须更改 Wildfly 配置的任何设置？我尝试了使用和不使用 maven 的代码。

我正在使用这个库来编译我的代码，就像我说的，它使用桌面之类的应用程序工作：https://github.com/trung/InMemoryJavaCompiler

错误：

13:44:57,686 ERROR [stderr] (default task-5) /br/com/project/webtest/service/CompileClass.java:2: error: package org.junit does not exist
13:44:57,686 ERROR [stderr] (default task-5) import static org.junit.Assert.*;
13:44:57,686 ERROR [stderr] (default task-5)                        ^
13:44:57,687 ERROR [stderr] (default task-5) /br/com/project/webtest/service/CompileClass.java:3: error: cannot find symbol
13:44:57,687 ERROR [stderr] (default task-5) import br.com.project.webtest.service.SeleniumService;
13:44:57,688 ERROR [stderr] (default task-5)                                               ^
13:44:57,688 ERROR [stderr] (default task-5)   symbol:   class SeleniumService
13:44:57,688 ERROR [stderr] (default task-5)   location: package br.com.project.webtest.service
13:44:57,689 ERROR [stderr] (default task-5) /br/com/project/webtest/service/CompileClass.java:4: error: package org.junit does not exist
13:44:57,689 ERROR [stderr] (default task-5) import org.junit.*;

错误消息继续出现在所有其他导入库中然后是类格式错误：

13:44:57,751 WARNING [javax.enterprise.resource.webcontainer.jsf.lifecycle] (default task-5) #{testController.action()}: java.lang.ClassFormatError: Truncated class file: javax.faces.FacesException: #{testController.action()}: java.lang.ClassFormatError: Truncated class file

编辑：我使用 eclipse mars 添加，在 Webcontent/web-inf/lib 文件夹下，添加我的库并右键单击，添加到构建路径。

编辑 2：负责创建代码并获取结果的类：

package br.com.test;

import java.io.IOException;
import java.nio.charset.Charset;
import java.nio.file.Files;
import java.nio.file.Paths;

import javax.faces.bean.ManagedBean;
import javax.faces.bean.SessionScoped;

@ManagedBean
@SessionScoped
public class TestController {

    public void actionParent() {
        String javaCode = generateJavaCode();
        Class<?> compile = null;
        try {
            compile = InMemoryCompilerTest.compile(Thread.currentThread().getContextClassLoader(),
                    "br.com.project.webtest.service.CompileClass", javaCode);
            System.out.println("Worked: " + compile);
        } catch (Exception e) {
            e.printStackTrace();
        }           
    }

    public void actionClassLoader() {
        String javaCode = generateJavaCode();
        Class<?> compile = null;
        try {
            compile = InMemoryCompilerTest.compile("br.com.project.webtest.service.CompileClass", javaCode);
            System.out.println("Worked: " + compile);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    static String readFile(String path, Charset encoding) throws IOException {
        byte[] encoded = Files.readAllBytes(Paths.get(path));
        return new String(encoded, encoding);
    }

    private static String generateJavaCode() {
        String java = "package br.com.project.webtest.service;\r\n" 
                    + "import static org.junit.Assert.*;\r\n"
                    + "public class CompileClass {\r\n" 
                    + " public CompileClass() {\r\n"
                    + "     System.out.println(\"Dynamically compiled\");\r\n"
                    + "     String text = \"Testing JUnit lib\";\r\n"
                    + "     assertEquals(\"Testing JUnit lib\", text);\r\n" 
                    + "     System.out.println(\"completed\");\r\n"
                    + " }\r\n" + "  public static void main(String[] args) {\r\n" 
                    + "     new CompileClass();\r\n"
                    + "     System.out.println(\"finish\");\r\n" 
                    + " }\r\n" 
                    + "}\r\n";

        return java;

    }

    public static void main(String[] args)  {
        TestController c = new TestController();
        c.actionClassLoader();
        c.actionParent();
    }

}

我创建了一个扩展 lib 的类并更改了使用父类加载器：

public class InMemoryCompilerTest extends InMemoryJavaCompiler {
    static JavaCompiler javac = ToolProvider.getSystemJavaCompiler();

    public static Class<?> compile(ClassLoader parent, String className, String sourceCodeInText) throws Exception {
        SourceCode sourceCode = new SourceCode(className, sourceCodeInText);
        CompiledCode compiledCode = new CompiledCode(className);
        Iterable<? extends JavaFileObject> compilationUnits = Arrays.asList(sourceCode);
        DynamicClassLoader cl = new DynamicClassLoader(parent);
        ExtendedStandardJavaFileManager fileManager = new ExtendedStandardTest(
                javac.getStandardFileManager(null, null, null), compiledCode, cl);
        JavaCompiler.CompilationTask task = javac.getTask(null, fileManager, null, null, null, compilationUnits);
        boolean result = task.call();
        return cl.loadClass(className);
    }
}

public class ExtendedStandardTest extends ExtendedStandardJavaFileManager{

    protected ExtendedStandardTest(JavaFileManager fileManager, CompiledCode compiledCode, DynamicClassLoader cl) {
        super(fileManager, compiledCode, cl);
    }

}

xhtml:

<html xmlns="http://www.w3.org/1999/xhtml" xmlns:ui="http://java.sun.com/jsf/facelets" xmlns:f="http://java.sun.com/jsf/core" xmlns:h="http://java.sun.com/jsf/html">

<h:head></h:head>
<h:body>

    <h:form>

        <h:commandButton action="#{testController.actionClassLoader()}" value="ClassLoader" />
        <h:commandButton action="#{testController.actionParent()}" value="Parent" />
    </h:form>
</h:body>
</html>

我按照您的建议测试了通过父类加载器，但也没有用。

第一个类“TestController”从它的主要方法执行。

编辑：

我添加了以下代码，我可以在其中使用我的库设置类路径：

// set the classpath
        List<String> options = new ArrayList<String>();

        options.add("-classpath");
        StringBuilder sb = new StringBuilder();
        URLClassLoader urlClassLoader = (URLClassLoader) parent;

        for (URL url : urlClassLoader.getURLs()) {
            sb.append(url.getFile()).append(File.pathSeparator);
        }
        options.add(sb.toString());

作为返回的 Java 应用程序执行：

[-classpath, /C:/Users/dev/Automacao/workspace/test/build/classes/;/C:/Users/dev/Automacao/workspace/test/WebContent/WEB-INF/lib/InMemoryJavaCompiler-1.2.jar;/C:/Users/dev/Automacao/workspace/test/WebContent/WEB-INF/lib/commons-io-2.5.jar;/C:/Users/dev/Automacao/workspace/test/WebContent/WEB-INF/lib/workspace_libs/client-combined-3.0.0-beta3-nodeps.jar;/C:/Users/dev/Automacao/workspace/test/WebContent/WEB-INF/lib/workspace_libs/commons-codec-1.10.jar;/C:/Users/dev/Automacao/workspace/test/WebContent/WEB-INF/lib/workspace_libs/commons-exec-1.3.jar;/C:/Users/dev/Automacao/workspace/test/WebContent/WEB-INF/lib/workspace_libs/commons-logging-1.2.jar;/C:/Users/dev/Automacao/workspace/test/WebContent/WEB-INF/lib/workspace_libs/gson-2.3.1.jar;/C:/Users/dev/Automacao/workspace/test/WebContent/WEB-INF/lib/workspace_libs/guava-19.0.jar;/C:/Users/dev/Automacao/workspace/test/WebContent/WEB-INF/lib/workspace_libs/hamcrest-core-1.3.jar;/C:/Users/dev/Automacao/workspace/test/WebContent/WEB-INF/lib/workspace_libs/hamcrest-library-1.3.jar;/C:/Users/dev/Automacao/workspace/test/WebContent/WEB-INF/lib/workspace_libs/httpclient-4.5.2.jar;/C:/Users/dev/Automacao/workspace/test/WebContent/WEB-INF/lib/workspace_libs/httpcore-4.4.4.jar;/C:/Users/dev/Automacao/workspace/test/WebContent/WEB-INF/lib/workspace_libs/httpmime-4.5.2.jar;/C:/Users/dev/Automacao/workspace/test/WebContent/WEB-INF/lib/workspace_libs/jna-4.1.0.jar;/C:/Users/dev/Automacao/workspace/test/WebContent/WEB-INF/lib/workspace_libs/jna-platform-4.1.0.jar;/C:/Users/dev/Automacao/workspace/test/WebContent/WEB-INF/lib/workspace_libs/junit-4.12.jar;/C:/Users/dev/Automacao/workspace/test/WebContent/WEB-INF/lib/workspace_libs/netty-3.5.7.Final.jar;/C:/Users/dev/Automacao/workspace/test/WebContent/WEB-INF/lib/workspace_libs/phantomjsdriver-1.3.0.jar;/C:/Users/dev/Automacao/workspace/test/WebContent/WEB-INF/lib/workspace_libs/cglib-nodep-3.2.4.jar;/C:/Program%20Files/Apache%20Software%20Foundation/Apache%20Tomcat%208.0.3/lib/annotations-api.jar;/C:/Program%20Files/Apache%20Software%20Foundation/Apache%20Tomcat%208.0.3/lib/catalina-ant.jar;/C:/Program%20Files/Apache%20Software%20Foundation/Apache%20Tomcat%208.0.3/lib/catalina-ha.jar;/C:/Program%20Files/Apache%20Software%20Foundation/Apache%20Tomcat%208.0.3/lib/catalina-storeconfig.jar;/C:/Program%20Files/Apache%20Software%20Foundation/Apache%20Tomcat%208.0.3/lib/catalina-tribes.jar;/C:/Program%20Files/Apache%20Software%20Foundation/Apache%20Tomcat%208.0.3/lib/catalina.jar;/C:/Program%20Files/Apache%20Software%20Foundation/Apache%20Tomcat%208.0.3/lib/ecj-4.3.1.jar;/C:/Program%20Files/Apache%20Software%20Foundation/Apache%20Tomcat%208.0.3/lib/el-api.jar;/C:/Program%20Files/Apache%20Software%20Foundation/Apache%20Tomcat%208.0.3/lib/jasper-el.jar;/C:/Program%20Files/Apache%20Software%20Foundation/Apache%20Tomcat%208.0.3/lib/jasper.jar;/C:/Program%20Files/Apache%20Software%20Foundation/Apache%20Tomcat%208.0.3/lib/jsp-api.jar;/C:/Program%20Files/Apache%20Software%20Foundation/Apache%20Tomcat%208.0.3/lib/servlet-api.jar;/C:/Program%20Files/Apache%20Software%20Foundation/Apache%20Tomcat%208.0.3/lib/tomcat-api.jar;/C:/Program%20Files/Apache%20Software%20Foundation/Apache%20Tomcat%208.0.3/lib/tomcat-coyote.jar;/C:/Program%20Files/Apache%20Software%20Foundation/Apache%20Tomcat%208.0.3/lib/tomcat-dbcp.jar;/C:/Program%20Files/Apache%20Software%20Foundation/Apache%20Tomcat%208.0.3/lib/tomcat-i18n-es.jar;/C:/Program%20Files/Apache%20Software%20Foundation/Apache%20Tomcat%208.0.3/lib/tomcat-i18n-fr.jar;/C:/Program%20Files/Apache%20Software%20Foundation/Apache%20Tomcat%208.0.3/lib/tomcat-i18n-ja.jar;/C:/Program%20Files/Apache%20Software%20Foundation/Apache%20Tomcat%208.0.3/lib/tomcat-jdbc.jar;/C:/Program%20Files/Apache%20Software%20Foundation/Apache%20Tomcat%208.0.3/lib/tomcat-jni.jar;/C:/Program%20Files/Apache%20Software%20Foundation/Apache%20Tomcat%208.0.3/lib/tomcat-spdy.jar;/C:/Program%20Files/Apache%20Software%20Foundation/Apache%20Tomcat%208.0.3/lib/tomcat-util-scan.jar;/C:/Program%20Files/Apache%20Software%20Foundation/Apache%20Tomcat%208.0.3/lib/tomcat-util.jar;/C:/Program%20Files/Apache%20Software%20Foundation/Apache%20Tomcat%208.0.3/lib/tomcat-websocket.jar;/C:/Program%20Files/Apache%20Software%20Foundation/Apache%20Tomcat%208.0.3/lib/websocket-api.jar;/C:/Users/dev/Automacao/workspace/libraries/JSF%202.2%20(Mojarra%202.2.0)/mojarra-2.2.0-FCS/lib/javax.faces.jar;]

作为网络应用程序执行：

[-classpath, /C:/Users/dev/Automacao/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/test/WEB-INF/classes/;/C:/Users/dev/Automacao/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/test/WEB-INF/lib/commons-io-2.5.jar;/C:/Users/dev/Automacao/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/test/WEB-INF/lib/InMemoryJavaCompiler-1.2.jar;/C:/Users/dev/Automacao/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/test/WEB-INF/lib/javax.faces.jar;]

我怎样才能得到相同的结果？

【问题讨论】：

您应该描述如何将它们添加到类路径中
@NicolasFilotto，已编辑。我像往常一样添加。右键添加到构建路径。我也尝试使用 Maven。库导出到war项目，但动态尝试编译时找不到。
请同时显示您用于编译的代码
@NicolasFilotto 已更新。尝试了您的答案建议，但没有奏效。

标签： java jakarta-ee classpath wildfly-9

【解决方案1】：

让它工作。

我必须进行@NicolasFilotto 提到的更改，以便在使用 web 应用程序时使用父类加载器。之后，对于 JavaCompiler 的工作，因为我正在使用外部库，所以有必要像我上次编辑中提到的那样传递我的类路径。基本上代码改为：

public static Class<?> compile(ClassLoader parent, String className, String sourceCodeInText) throws Exception {
        SourceCode sourceCode = new SourceCode(className, sourceCodeInText);
        CompiledCode compiledCode = new CompiledCode(className);
        Iterable<? extends JavaFileObject> compilationUnits = Arrays.asList(sourceCode);
        DynamicClassLoader cl = new DynamicClassLoader(parent);
        ExtendedStandardJavaFileManager fileManager = new ExtendedStandard(
                javac.getStandardFileManager(null, null, null), compiledCode, cl);

        // set the classpath
        List<String> options = new ArrayList<String>();

        options.add("-classpath");
        StringBuilder sb = new StringBuilder();
        Enumeration<URL> resources = parent.getResources("/");
        while (resources.hasMoreElements()) {
            URL url = resources.nextElement();
            sb.append(url.getFile()).append(File.pathSeparator);
        }

        options.add(sb.toString());

        // execute the compiler
        Boolean call = javac.getTask(null, fileManager, null, options, null, compilationUnits).call();
        if (call) {
            return cl.loadClass(className);
        }
        return null;
    }

使用 wildfly 我必须将 URLClassLoader urlClassLoader = (URLClassLoader) parent; 更改为 Enumeration<URL> resources = parent.getResources("/");

【讨论】：

这个解决方案对我来说就像一个魅力！谢谢！！我正在使用 Apache Tomcat 8。我唯一需要修改的是删除感叹号“！”在每个类路径的末尾。我不知道为什么，但在我的类加载器中，所有路径都被排除在外。我这样做了：url.replaceAll("!", ""); 添加到 sb 之前的字符串，它工作正常！！

【解决方案2】：

@VictorBello 我已经在Dynamic Loader 中实现了这些功能。甚至你可以在运行时将 Jar 包含在 Dynamic Loader

public void DynamicJarCodeTest() throws Exception {
    try {
        StringBuilder sourceCode = new StringBuilder();
        sourceCode.append("package org.dvare.dynamic;\n");
        sourceCode.append("import org.apache.commons.math3.Field;\n");
        sourceCode.append("public class SourceClass {\n");
        sourceCode.append("   public String test() { \n");
        sourceCode.append("   return \"inside test method\";\n");
        sourceCode.append("   }\n");
        sourceCode.append("}");


        DynamicCompiler dynamicCompiler = new DynamicCompiler();
        dynamicCompiler.setSeparateContext(true);
        dynamicCompiler.setUpdateContextClassLoader(false);

        dynamicCompiler.addJar(getClass().getClassLoader().getResource("commons-math3.jar"));
        dynamicCompiler.addSource("org.dvare.dynamic.SourceClass", sourceCode.toString());
        dynamicCompiler.build();

        Class aClass = Class.forName("org.apache.commons.math3.Field", false, dynamicCompiler.getClassLoader());
        Assert.assertNotNull(aClass);

        Class bClass = Class.forName("org.dvare.dynamic.SourceClass", false, dynamicCompiler.getClassLoader());
        Assert.assertNotNull(bClass);


    } catch (DynamicCompilerException e) {
        System.out.println(e.getErrorList());
    } catch (Exception e) {
        e.printStackTrace();
    }

}

【讨论】：

感谢您的回答@Hammad，但我无法使用您的库来完成这项工作。我刚刚为我的示例更改了“addSource”和“sourceCode”，但出现错误：[{kind=ERROR, line=4, message=package org.junit does not exist}, {kind=ERROR, line=9, message=cannot find symbol symbol: method assertEquals(java.lang.String,java.lang.String) location: class br.com.project.webtest.service.CompileClass}]。我还尝试添加我的 lib 文件夹中的 jar，但无法正常工作。
看到这一行 package 'org.junit' does not exist 意味着未找到junit依赖项在构建路径中包含junit依赖项或使用add jar从库中添加jar
我理解错误，问题是junit lib包含在我的buildbath中，我得到了这个错误。
options里面DynamicCompiler得到这个路径，是正确的file:/C:/Users/dev/Automacao/workspace/test/WebContent/WEB-INF/lib/junit-4.12.jar;

【解决方案3】：

感谢@victor-bello 的出色解决方案。我的解决方案如下所示：

需要将所有 jar 从您的 maven 存储库复制到一个文件夹中，并将该文件夹与您的应用程序一起分发：
从中生成 javac 的类路径（愚蠢的方式）：

从 github 复制 InMemoryJavaCompiler 代码源并覆盖：

公共类 InMemoryCompilerTest 扩展 InMemoryJavaCompiler {

static JavaCompiler javac = ToolProvider.getSystemJavaCompiler();

public static Class<?> compile(ClassLoader parent, String className, String sourceCodeInText, String classpath ) throws Exception {

    SourceCode sourceCode = new SourceCode(className, sourceCodeInText);
    CompiledCode compiledCode = new CompiledCode(className);
    Iterable<? extends JavaFileObject> compilationUnits = Arrays.asList(sourceCode);
    DynamicClassLoader cl = new DynamicClassLoader(parent);
    ExtendedStandardJavaFileManager fileManager =
            new ExtendedStandard(javac.getStandardFileManager(null, null, null), compiledCode, cl);

    // set the classpath
    List<String> options = new ArrayList<String>();

    options.add("-classpath");
    options.add(classpath);

    // execute the compiler
    Boolean call = javac.getTask(null, fileManager, null, options, null, compilationUnits).call();
    if (call) {
        return cl.loadClass(className);
    }
    return null;
}

}

调用编译方法：

类 testClass = inMemoryCompilerTest.compile(Thread.currentThread().getContextClassLoader(),"com.namespace.here.ClassName", someCode, stringBuilder.toString());

【讨论】：